# Homework Circuit - design a digital decoder.

Discussion in 'Homework Help' started by Leite33, Nov 28, 2015.

1. ### Leite33 Thread Starter Member

Nov 28, 2015
57
0
Dear friends
I have a difficult home work and i want your help. I have to create a circuit on a paper.
" Create a circuit production digitized par values for a number of three bits using (xyz)
j) decoders 2 to 4 (with a non-inverted outputs and without activated entrance) and gates OR
ii)Only multiplexers 2 to 1 (without activated entrance) and gates NOT

2. ### shteii01 AAC Fanatic!

Feb 19, 2010
3,387
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I see two problems.
One of them is language.

3. ### Leite33 Thread Starter Member

Nov 28, 2015
57
0
I am sorry english is not my mother language.
Create a circuit to produce a bit of positive rate for a number of 3 binary bits (xyz) using:
1.decoders 2 to 4 (with non inverted outputs and without activated entrance) and OR gates
2. only multiplexers 2 to 1 (without activated entrance) and AND gates

My circuit will have entrances x y z and output 1 bit using decoders and OR gates

4. ### WBahn Moderator

Mar 31, 2012
17,743
4,795
You need to describe more fully what you mean by "a bit of positive rate" for a "number of 3 binary bits"?

Perhaps a couple examples might help get your meaning across.

5. ### Dodgydave Distinguished Member

Jun 22, 2012
4,986
745
Use the words "inputs" for entrance,

What's positive rate,is that a positive output signal?

Last edited: Nov 29, 2015
6. ### Leite33 Thread Starter Member

Nov 28, 2015
57
0
Yes my output must be one positive byte(8bits) like 10010000 for example and not 10000000

Nov 28, 2015
57
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Any help?

8. ### Leite33 Thread Starter Member

Nov 28, 2015
57
0
How i can built a small circuit with 2 for example decoder 2-4 and some OR gates that should have inputs xyz (3 inputs)

May 21, 2014
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Nov 28, 2015
57
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Greek

11. ### ISB123 Well-Known Member

May 21, 2014
1,239
527
Post the same question in Greek pretty sure we have a Greek guy around here.

12. ### WBahn Moderator

Mar 31, 2012
17,743
4,795
Why is 1001000 considered "one positive byte" while 1000000 is not?

It sounds like your input is a 3-bit value, xyz, where x, y, and z are each one bit. Where does this requirement that the output be eight bits come from?

Can you describe, in words, how YOU would look at the inputs and determine what the output should be?

13. ### panic mode Senior Member

Oct 10, 2011
1,320
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maybe bit4 is sign bit

14. ### WBahn Moderator

Mar 31, 2012
17,743
4,795
Maybe. But unless the TS can communicate the situation clearly, we are all just guessing.

15. ### Leite33 Thread Starter Member

Nov 28, 2015
57
0
Ok i will try be more specifiec. I want to make a simple circuit with 3 inputs x y z that should produce a byte (for example 11011011) by using 2 decoders and one OR gate if this is possible

16. ### ISB123 Well-Known Member

May 21, 2014
1,239
527
Make a schematic which describes how you would design a such circuit.
We cant help unless you show us some effort be it wrong or correct.

17. ### WBahn Moderator

Mar 31, 2012
17,743
4,795
But how does the output relate to these three inputs?

Are the three inputs three bits, three bytes, three giraffes, what?

18. ### hp1729 Well-Known Member

Nov 23, 2015
1,951
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A three input decoder? Look at the data sheet for a decoder like the 74138 and modify it as needed.

19. ### Whatashame Member

Nov 30, 2015
83
12
This is for WBahn. Your a pain in the a*#. I'm staring at"Ohm's law. Vx I= W. Thank you! By the way if you ever get hit with 600 volts you better pray it's AC volts and not DC volts. You might fly through a wall with AC but with DC your stuck on it until your fried or someone hits you off with a baseball bat. I hit you off if need be. I'm leaving this site. On it one day. Be kind to new bed and all people. I used lay terms. You must be an engineer. I bow down, Almighty. [Name and phone number removed]. This was directed to WBahn, the most perfect person.

MOD NOTE: It's not a good idea to put personal contact info into publically accessible forums -- spam bots routinely sweep them up.

Last edited by a moderator: Dec 1, 2015
20. ### JoeJester AAC Fanatic!

Apr 26, 2005
3,373
1,159
The emphasis is "can" be stuck. I've been hung up on a +900V DC circuit for over what seemed like a couple of seconds until I managed to free myself. The circuit was a 300 mA circuit.

In my defense, and there really wasn't a defense because I hadn't taken the time to read the technical manual, I didn't know that equipment used switched screen grid voltage to key the transmitter vice switched B+. It was that time that I chose to stand up to anyone who viewed myself or my technicians "reading the manual" as not working. After all, we were overhauling quite a few equipments that we were not taught in the schools or at previous units. I had a not so nice heart to heart conversation with those senior to me, I was a Petty Officer Second Class at the time. They asked me to talk about it during the training session I had scheduled the following week, and did express my opine on the importance of RYDM ... Read Your Dam Mannual.